//package com.dn.dngateway;
//
//import java.util.Date;
//
//import cn.hutool.core.collection.CollectionUtil;
//import cn.hutool.core.util.StrUtil;
//import cn.hutool.json.JSON;
//import com.dn.dngateway.model.GatewayLog;
//import com.dn.dngateway.service.AccessLogService;
//import com.google.gson.Gson;
//import lombok.extern.slf4j.Slf4j;
//import org.reactivestreams.Publisher;
//import org.springframework.beans.factory.annotation.Autowired;
//import org.springframework.cloud.gateway.filter.GatewayFilterChain;
//import org.springframework.cloud.gateway.filter.GlobalFilter;
//import org.springframework.cloud.gateway.filter.factory.rewrite.CachedBodyOutputMessage;
//import org.springframework.cloud.gateway.route.Route;
//import org.springframework.cloud.gateway.support.BodyInserterContext;
//import org.springframework.cloud.gateway.support.ServerWebExchangeUtils;
//import org.springframework.core.Ordered;
//import org.springframework.core.ResolvableType;
//import org.springframework.core.io.buffer.*;
//import org.springframework.http.HttpHeaders;
//import org.springframework.http.MediaType;
//import org.springframework.http.codec.HttpMessageReader;
//import org.springframework.http.codec.multipart.FormFieldPart;
//import org.springframework.http.codec.multipart.Part;
//import org.springframework.http.server.reactive.ServerHttpRequest;
//import org.springframework.http.server.reactive.ServerHttpRequestDecorator;
//import org.springframework.http.server.reactive.ServerHttpResponse;
//import org.springframework.http.server.reactive.ServerHttpResponseDecorator;
//import org.springframework.stereotype.Component;
//import org.springframework.util.LinkedMultiValueMap;
//import org.springframework.util.MultiValueMap;
//import org.springframework.web.reactive.function.BodyInserter;
//import org.springframework.web.reactive.function.BodyInserters;
//import org.springframework.web.reactive.function.server.HandlerStrategies;
//import org.springframework.web.reactive.function.server.ServerRequest;
//import org.springframework.web.server.ServerWebExchange;
//import org.springframework.web.util.UriComponentsBuilder;
//import reactor.core.publisher.Flux;
//import reactor.core.publisher.Mono;
//
//import javax.annotation.Resource;
//import java.nio.charset.StandardCharsets;
//import java.util.*;
//
///**
// * /**
// * 全局拦截器，作用所有的微服务
// * 1. 对请求的API调用过滤，记录接口的请求时间，方便日志审计、告警、分析等运维操作
// * 2. 后期可以扩展对接其他日志系统
// */
//@Slf4j
//@Component
//public class AccessLogFilterDemo implements GlobalFilter, Ordered {
//
//    /**
//     * default HttpMessageReader.
//     */
//    private static final List<HttpMessageReader<?>> MESSAGE_READERS = HandlerStrategies.withDefaults().messageReaders();
//
//    @Resource
//    private AccessLogService accessLogService;
//
//    private final List<HttpMessageReader<?>> messageReaders = HandlerStrategies.withDefaults().messageReaders();
//
//
//    /**
//     * 顺序必须是<-1，否则标准的NettyWriteResponseFilter将在您的过滤器得到一个被调用的机会之前发送响应
//     * 也就是说如果不小于 -1 ，将不会执行获取后端响应的逻辑
//     *
//     * @return
//     */
//    @Override
//    public int getOrder() {
//        return -100;
//    }
//
//    @Override
//    @SuppressWarnings("unchecked")
//    public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
//
//        ServerHttpRequest request = exchange.getRequest();
//        // 请求路径
//        String requestPath = request.getPath().pathWithinApplication().value();
//        Route route = getGatewayRoute(exchange);
////        String ipAddress = IpUtils.getIpAddress(request);
//        String ipAddress = request.getLocalAddress().getHostString();
//
//        GatewayLog gatewayLog = new GatewayLog();
//        // 协议
//        gatewayLog.setSchema(request.getURI().getScheme());
//        // 请求方法
//        gatewayLog.setRequestMethod(request.getMethodValue());
//        // 请求路径
//        gatewayLog.setRequestPath(requestPath);
//        // 访问实例
//        gatewayLog.setTargetServer(route.getId());
//        // 请求时间
//        gatewayLog.setRequestTime(new Date());
//        // 请求ip
//        gatewayLog.setIp(ipAddress);
//
//        MediaType mediaType = request.getHeaders().getContentType();
//        // 请求数据类型
//        gatewayLog.setRequestContentType(mediaType.getType() + "/" + mediaType.getSubtype());
//        //json格式
//        if (MediaType.APPLICATION_JSON.isCompatibleWith(mediaType)) {
//            return writeBodyLog(exchange, chain, gatewayLog);
//        }
//        //form-data格式
//        else if (MediaType.MULTIPART_FORM_DATA.isCompatibleWith(mediaType) || MediaType.APPLICATION_FORM_URLENCODED.isCompatibleWith(mediaType)) {
//            return readFormData(exchange, chain, gatewayLog);
//        }
//        //其他格式
//        else {
//            return writeBasicLog(exchange, chain, gatewayLog);
//        }
//    }
//
//    private Mono<Void> writeBasicLog(ServerWebExchange exchange, GatewayFilterChain chain, GatewayLog accessLog) {
//
//        return DataBufferUtils.join(exchange.getRequest().getBody()).flatMap(dataBuffer -> {
//            DataBufferUtils.retain(dataBuffer);
//            final Flux<DataBuffer> cachedFlux = Flux.defer(() -> Flux.just(dataBuffer.slice(0, dataBuffer.readableByteCount())));
//            final ServerHttpRequest mutatedRequest = new ServerHttpRequestDecorator(exchange.getRequest()) {
//                @Override
//                public Flux<DataBuffer> getBody() {
//                    return cachedFlux;
//                }
//
//                @Override
//                public MultiValueMap<String, String> getQueryParams() {
//                    return UriComponentsBuilder.fromUri(exchange.getRequest().getURI()).build().getQueryParams();
//                }
//
//            };
//
//            StringBuilder builder = new StringBuilder();
//            MultiValueMap<String, String> queryParams = exchange.getRequest().getQueryParams();
//            if (CollectionUtil.isNotEmpty(queryParams)) {
//                for (Map.Entry<String, List<String>> entry : queryParams.entrySet()) {
////                    builder.append(entry.getKey()).append("=").append(StrUtil.join(entry.getValue(), ","));
//                    builder.append(entry.getKey()).append("=").append(StrUtil.join(",", entry.getValue()));
//                }
//            }
//
//            accessLog.setRequestBody(builder.toString());
//
//            //获取响应体
//            ServerHttpResponseDecorator decoratedResponse = recordResponseLog(exchange, accessLog);
//
//            return chain.filter(exchange.mutate().request(mutatedRequest).response(decoratedResponse).build())
//                    .then(Mono.fromRunnable(() -> {
//                        // 打印日志
//                        writeAccessLog(accessLog);
//                        Gson gson = new Gson();
//                        String json = gson.toJson(accessLog);
//                        System.out.println(json);
//                    }));
//        });
//    }
//
//    /**
//     * 读取form-data数据
//     *
//     * @param exchange
//     * @param chain
//     * @param accessLog
//     * @return
//     */
//    private Mono<Void> readFormData(ServerWebExchange exchange, GatewayFilterChain chain, GatewayLog accessLog) {
//
//        return DataBufferUtils.join(exchange.getRequest().getBody()).flatMap(dataBuffer -> {
//            DataBufferUtils.retain(dataBuffer);
//            final Flux<DataBuffer> cachedFlux = Flux.defer(() -> Flux.just(dataBuffer.slice(0, dataBuffer.readableByteCount())));
//            final ServerHttpRequest mutatedRequest = new ServerHttpRequestDecorator(exchange.getRequest()) {
//                @Override
//                public Flux<DataBuffer> getBody() {
//                    return cachedFlux;
//                }
//
//                @Override
//                public MultiValueMap<String, String> getQueryParams() {
//                    return UriComponentsBuilder.fromUri(exchange.getRequest().getURI()).build().getQueryParams();
//                }
//            };
//
//            final HttpHeaders headers = exchange.getRequest().getHeaders();
//            if (headers.getContentLength() == 0) {
//                return chain.filter(exchange);
//            }
//
//            ResolvableType resolvableType;
//            if (MediaType.MULTIPART_FORM_DATA.isCompatibleWith(headers.getContentType())) {
//                resolvableType = ResolvableType.forClassWithGenerics(MultiValueMap.class, String.class, Part.class);
//            } else {
//                //解析 application/x-www-form-urlencoded
//                resolvableType = ResolvableType.forClass(String.class);
//            }
//
//            return MESSAGE_READERS.stream().filter(reader -> reader.canRead(resolvableType, mutatedRequest.getHeaders().getContentType())).findFirst()
//                    .orElseThrow(() -> new IllegalStateException("no suitable HttpMessageReader.")).readMono(resolvableType, mutatedRequest, Collections.emptyMap()).flatMap(resolvedBody -> {
//                        if (resolvedBody instanceof MultiValueMap) {
//                            LinkedMultiValueMap map = (LinkedMultiValueMap) resolvedBody;
//                            if (CollectionUtil.isNotEmpty(map)) {
//
//                                StringBuilder builder = new StringBuilder();
//
//                                final Part bodyPartInfo = (Part) ((MultiValueMap) resolvedBody).getFirst("body");
//                                if (bodyPartInfo instanceof FormFieldPart) {
//                                    String body = ((FormFieldPart) bodyPartInfo).value();
////                                    log.info("body ==== " + body);
//                                    builder.append("body=").append(body);
//                                }
//
//                                final Part uidPartInfo = (Part) ((MultiValueMap) resolvedBody).getFirst("uid");
//                                if (uidPartInfo instanceof FormFieldPart) {
//                                    String uid = ((FormFieldPart) uidPartInfo).value();
////                                    log.info("uid ==== " + uid);
//                                    accessLog.setUserId(uid);
//                                    if (builder.length() > 0) {
//                                        builder.append("&uid=").append(uid);
//                                    } else {
//                                        builder.append("uid=").append(uid);
//                                    }
//
//                                }
//
//                                final Part timeStampPartInfo = (Part) ((MultiValueMap) resolvedBody).getFirst("timeStamp");
//                                if (timeStampPartInfo instanceof FormFieldPart) {
//                                    String timeStamp = ((FormFieldPart) timeStampPartInfo).value();
////                                    log.info("timeStamp ==== " + timeStamp );
//                                    if (builder.length() > 0) {
//                                        builder.append("&timeStamp=").append(timeStamp);
//                                    } else {
//                                        builder.append("timeStamp=").append(timeStamp);
//                                    }
//
//                                }
//
//                                final Part tokenPartInfo = (Part) ((MultiValueMap) resolvedBody).getFirst("token");
//                                if (tokenPartInfo instanceof FormFieldPart) {
//                                    String token = ((FormFieldPart) tokenPartInfo).value();
////                                    log.info("token ==== " + token);
//                                    if (builder.length() > 0) {
//                                        builder.append("&token=").append(token);
//                                    } else {
//                                        builder.append("token=").append(token);
//                                    }
//
//                                }
//
//                                final Part signPartInfo = (Part) ((MultiValueMap) resolvedBody).getFirst("sign");
//                                if (signPartInfo instanceof FormFieldPart) {
//                                    String sign = ((FormFieldPart) signPartInfo).value();
////                                    log.info("sign ==== " + sign);
//                                    if (builder.length() > 0) {
//                                        builder.append("&sign=").append(sign);
//                                    } else {
//                                        builder.append("sign=").append(sign);
//                                    }
//                                }
//
//                                accessLog.setRequestBody(builder.toString());
//                            }
//                        } else {
//                            accessLog.setRequestBody((String) resolvedBody);
//                        }
//
//                        //获取响应体
//                        ServerHttpResponseDecorator decoratedResponse = recordResponseLog(exchange, accessLog);
//
//                        return chain.filter(exchange.mutate().request(mutatedRequest).response(decoratedResponse).build())
//                                .then(Mono.fromRunnable(() -> {
//                                    // 打印日志
//                                    writeAccessLog(accessLog);
//                                }));
//                    });
//
//        });
//    }
//
//
//    /**
//     * 解决 request body 只能读取一次问题，
//     * 参考: org.springframework.cloud.gateway.filter.factory.rewrite.ModifyRequestBodyGatewayFilterFactory
//     *
//     * @param exchange
//     * @param chain
//     * @param gatewayLog
//     * @return
//     */
//    @SuppressWarnings("unchecked")
//    private Mono writeBodyLog(ServerWebExchange exchange, GatewayFilterChain chain, GatewayLog gatewayLog) {
//        ServerRequest serverRequest = ServerRequest.create(exchange, messageReaders);
//
//        Mono<String> modifiedBody = serverRequest.bodyToMono(String.class)
//                .flatMap(body -> {
//                    gatewayLog.setRequestBody(body);
//                    return Mono.just(body);
//                });
//
//        // 通过 BodyInserter 插入 body(支持修改body), 避免 request body 只能获取一次
//        BodyInserter bodyInserter = BodyInserters.fromPublisher(modifiedBody, String.class);
//        HttpHeaders headers = new HttpHeaders();
//        headers.putAll(exchange.getRequest().getHeaders());
//        // the new content type will be computed by bodyInserter
//        // and then set in the request decorator
//        headers.remove(HttpHeaders.CONTENT_LENGTH);
//
//        CachedBodyOutputMessage outputMessage = new CachedBodyOutputMessage(exchange, headers);
//
//        return bodyInserter.insert(outputMessage, new BodyInserterContext())
//                .then(Mono.defer(() -> {
//                    // 重新封装请求
//                    ServerHttpRequest decoratedRequest = requestDecorate(exchange, headers, outputMessage);
//
//                    // 记录响应日志
//                    ServerHttpResponseDecorator decoratedResponse = recordResponseLog(exchange, gatewayLog);
//
//                    // 记录普通的
//                    return chain.filter(exchange.mutate().request(decoratedRequest).response(decoratedResponse).build())
//                            .then(Mono.fromRunnable(() -> {
//                                // 打印日志
//                                writeAccessLog(gatewayLog);
//                            }));
//                }));
//    }
//
//    /**
//     * 打印日志
//     *
//     * @param gatewayLog 网关日志
//     * @author javadaily
//     * @date 2021/3/24 14:53
//     */
//    private void writeAccessLog(GatewayLog gatewayLog) {
//        accessLogService.saveAccessLog(gatewayLog);
//    }
//
//
//    private Route getGatewayRoute(ServerWebExchange exchange) {
//        return exchange.getAttribute(ServerWebExchangeUtils.GATEWAY_ROUTE_ATTR);
//    }
//
//
//    /**
//     * 请求装饰器，重新计算 headers
//     *
//     * @param exchange
//     * @param headers
//     * @param outputMessage
//     * @return
//     */
//    private ServerHttpRequestDecorator requestDecorate(ServerWebExchange exchange, HttpHeaders headers,
//                                                       CachedBodyOutputMessage outputMessage) {
//        return new ServerHttpRequestDecorator(exchange.getRequest()) {
//            @Override
//            public HttpHeaders getHeaders() {
//                long contentLength = headers.getContentLength();
//                HttpHeaders httpHeaders = new HttpHeaders();
//                httpHeaders.putAll(super.getHeaders());
//                if (contentLength > 0) {
//                    httpHeaders.setContentLength(contentLength);
//                } else {
//                    // TODO: this causes a 'HTTP/1.1 411 Length Required' // on
//                    // httpbin.org
//                    httpHeaders.set(HttpHeaders.TRANSFER_ENCODING, "chunked");
//                }
//                return httpHeaders;
//            }
//
//            @Override
//            public Flux<DataBuffer> getBody() {
//                return outputMessage.getBody();
//            }
//        };
//    }
//
//
//    /**
//     * 记录响应日志
//     * 通过 DataBufferFactory 解决响应体分段传输问题。
//     */
//    private ServerHttpResponseDecorator recordResponseLog(ServerWebExchange exchange, GatewayLog gatewayLog) {
//        ServerHttpResponse response = exchange.getResponse();
//        DataBufferFactory bufferFactory = response.bufferFactory();
//
//        return new ServerHttpResponseDecorator(response) {
//            @Override
//            public Mono<Void> writeWith(Publisher<? extends DataBuffer> body) {
//                if (body instanceof Flux) {
//                    Date responseTime = new Date();
//                    gatewayLog.setResponseTime(responseTime);
//                    // 计算执行时间
//                    long executeTime = (responseTime.getTime() - gatewayLog.getRequestTime().getTime());
//
//                    gatewayLog.setExecuteTime(executeTime);
//
//                    // 获取响应类型，如果是 json 就打印
//                    String originalResponseContentType = exchange.getAttribute(ServerWebExchangeUtils.ORIGINAL_RESPONSE_CONTENT_TYPE_ATTR);
////                    log.info("originalResponseContentType =========== " + originalResponseContentType);
//
//                    gatewayLog.setResponseContentType(originalResponseContentType);
//
//                    gatewayLog.setCode(this.getStatusCode().value());
//
////                    if (ObjectUtils.equals(this.getStatusCode(), HttpStatus.OK)
////                            && !StringUtil.isNullOrEmpty(originalResponseContentType)
////                            && originalResponseContentType.contains("application/json")) {
//
//                    Flux<? extends DataBuffer> fluxBody = Flux.from(body);
//                    return super.writeWith(fluxBody.buffer().map(dataBuffers -> {
//
//                        // 合并多个流集合，解决返回体分段传输
//                        DataBufferFactory dataBufferFactory = new DefaultDataBufferFactory();
//                        DataBuffer join = dataBufferFactory.join(dataBuffers);
//                        byte[] content = new byte[join.readableByteCount()];
//                        join.read(content);
//
//                        // 释放掉内存
//                        DataBufferUtils.release(join);
//                        String responseResult = new String(content, StandardCharsets.UTF_8);
////                            log.info("responseResult =========== " + responseResult);
//                        gatewayLog.setResponseData(responseResult);
//
//                        return bufferFactory.wrap(content);
//                    }));
//                }
////                }
//
//                // if body is not a flux. never got there.
//                return super.writeWith(body);
//            }
//        };
//    }
//
//
//}